msem-instigator

Whenever you cast an instant or sorcery spell, target creature can't block this turn.

{T}: Target creature with power 2 or less can't be blocked this turn.

When Goblin Twinblades enters the battlefield, create a 1/1 red Goblin creature token.

Menace
Sacrifice a Goblin: Heartless Warleader gets +2/+2 until end of turn.

Other Pirates you control get +1/+0.
Whenever another Pirate enters the battlefield under your control, Hookhand Freebooter deals 1 damage to any target.
When Hookhand Freebooter dies, create a Bullet token. (It's an artifact with “{T}, Sacrifice this artifact: It deals 1 damage to any target.)

When Incense Stoker enters the battlefield, you may return target instant or sorcery card with mana value less than or equal to the number of differently named lands you control from your graveyard to your hand.

When Infested Goblin dies, choose target creature. At the beginning of your next upkeep, that creature's controller sacrifices it.

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)

Menace
{1}, Discard Jund Shardseeker: Search your library for a basic Swamp or Forest card, reveal it, put it into your hand, then shuffle.

First strike, haste
Whenever Kragnoss' Battlecharger attacks, it gets +1/+0 until end of turn for each attacking creature.

Haste
When Kragnoss, Rebellion Commander enters the battlefield, create a 1/1 red Goblin creature token.
Whenever a Goblin you control attacks, Kragnoss, Rebellion Commander deals 1 damage to target creature defending player controls.

Whenever Lackeybot deals damage to a player, choose an artifact card with mana value X or less at random, where X is the amount of damage dealt. You may create a token that's a copy of that card.

Flash
When Mennin Pack enters the battlefield, each opponent loses 1 life.
When Mennin Pack dies, each opponent discards a card.

Trample
Primitive Berserker's power is equal to the number of Goblins you control.

Whenever another Goblin you control attacks, you may pay {1}. If you do, it gets +1/+0 until end of turn.

Whenever Raging Warlord attacks, Goblins you control get +1/+0 until end of turn.

Prowess

At the beginning of combat on each of your turns, you may sacrifice a land or exile a land card from your graveyard. If you do, create two 1/1 red Goblin creature tokens with haste. Exile those tokens at the beginning of the next end step.

When Rubble Seer enters the battlefield, you may sacrifice a land or exile a land card from your graveyard. If you do, exile the top card of your library. Until the end of your next turn, you may play that card.

When Sha'Iv's Scout enters the battlefield, adjudicate. (Create a white Aura enchantment token with enchant creature and “Sacrifice this token: Untap enchanted creature” attached to target creature.)
Whenever an Aura enters the battlefield under your control, target creature can't block this turn.

When Slaug's Warhowler enters the battlefield, create a 1/1 red Goblin creature token with haste.
When Slaug's Warhowler dies, you may discard a card. If you do, draw a card.

Swiftstep Cliffdweller has haste as long as you control another Goblin.

Menace (This creature can't be blocked except by two or more creatures.)

Goblincycling {1}{R}, Warriorcycling {1}{R} ({1}{R}, Discard this card: Search your library for a Goblin or Warrior card, reveal it, and put it into your hand. Then shuffle.)

{T}, Sacrifice a permanent: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)